Password Strength Checker
Check how strong your password really is. Entropy, crack-time estimates, and pattern warnings.
🔒 Nothing you type here is sent anywhere — this check runs 100% in your browser.
Entropy — A rough measure of randomness in bits, based on password length and which character classes (lowercase, uppercase, digits, symbols) are actually used. More bits means more possible combinations an attacker has to try.
Crack time estimates — Two scenarios: a throttled online login form (roughly 100 guesses/second, typical of a service with basic rate-limiting) and a fast offline attack against a stolen, weakly-hashed password database (roughly 10 billion guesses/second on modern hardware). These are estimates, not guarantees — actual numbers depend heavily on how the target stores and rate-limits passwords.
Pattern detection — Flags passwords found in real-world breach lists, sequential runs (abc, 123, qwerty), and repeated characters (aaa) — all patterns that dramatically cut down the real search space an attacker needs to try, even though they don't reduce raw entropy math.
About Password Strength Checker
Password Strength Checker analyzes a password entirely in your browser — nothing is sent anywhere, ever. It estimates entropy (bits of randomness), flags common patterns (dictionary passwords, sequential runs like "abc" or "123", repeated characters), and estimates how long a brute-force attack would take under two scenarios: throttled online guessing and fast offline hash cracking.